GaN crystals can be grown with either cubic or hexagonal (also known as wurtzite) phases. All commercial GaN LEDs are based on hexagonal materials, typically grown on sapphire substrates. “The hexagonal phase typically forms most easily, as it is the lowest energy crystallographic structure. Previous attempts to grow cubic GaN crystal structures have produced poor quality, heavily defected mixed phase materials”, said Prof. Christian Wetzel, Professor of Physics, Applied Physics and Astronomy, and co-inventor of this patent. Prof Wetzel and Prof Steve Brueck are both recognized leaders in the research and development of LED-based solid-state lighting.